The images are taken with the edge of the camera case pressed right up against the ruler. You could probably remove casing to increase zoom slightly, or create a slot to slide a microscope slide into it. The camera has two focuses the first:
And the second (maximum zoom):
I am using my laptop screen as a typical screen and viewing the image at 100%. Poor mans calculations give you the following for the first focus and second focus:
1mm displayed over 40mm: zoom ~ 40x
1mm displayed over 150mm: zoom ~ 150x
(Note: Measuring magnification level is rubbish as it depends on screen the image is viewed on, so viewing it on a projector would make the statistics seem more impressive.)
The minimum zoom is less than this as we can move the camera further from the object:
Which is about 15x zoom. The microscope box states the zoom is between 10x and 200x, which from these tests seems a little over-exaggerated but not by much.